A phaser fires a nadion particle beam at its target. That sounds like inertial mass is involved so it doesn't reach light speed. Semi-out-of-universe we see how fast a phaser beam is: I'd estimate something around 80 kph. You can see it moving with the naked eye. But that might be just a way to tell a story; to establish causality to the audience: "Look! First the beam is here, now it's here, now something's exploding." So the audience knows why the enemy ship explodes: It was a phaser beam, going from here to there. So maybe we are just shown a "symbolic slo-mo" to let us know what's happening.

Are there any in-universe insights on how fast a phaser beam travels? E.g. can I escape (escape, not evade) one on full impulse?

  • My understanding is that a phaser beam travels at the speed of light. You could escape it, but you'd have to be traveling at warp speed.
    – Chahk
    Commented Apr 14, 2014 at 19:56
  • Don't apply real Physics.. It can travel even faster than light..
    – user931
    Commented Apr 14, 2014 at 22:06
  • @SachinShekhar - The canon(ish) quote is that they travel at lightspeed unless being fired from a ship travelling at warp.
    – Valorum
    Commented Apr 14, 2014 at 23:51
  • @Richard No, I am saying it "can" travel FTL in sci-fi. The question is good except that inertial mass involvement thing.
    – user931
    Commented Apr 15, 2014 at 5:42
  • The problem is that although the leading edge can be seen moving with the naked eye, when the angle of attack changes the entire phaser beam remains straight (which requires at least a very fast particle stream otherwise it would look bendy). So it's at best inconsistent and, at worst, a nonsense... Commented Oct 31, 2016 at 14:10

8 Answers 8


The "Voyager Technical Manual" (written by longtime Star Trek production staffers Michael Okuda and Rick Sternbach as an 'aide-memoire' for potential scriptwriters) specifically states that phaser beams travel at the speed of light.

enter image description here

This is backed up by another quote from the earlier "TNG Technical Manual" which clearly states that the beam travels at "c"

TNG Technical Manual

Given that full impulse is supposedly well short of the speed of light, the short answer to your question is "no, you cannot escape a phaser beam by travelling at sublight speeds".

Travelling at warp speed would be considerably more effective against a foe travelling below lightspeed since you would simply outrun the beam (unless the phaser is fired from a ship travelling at a similar warp factor).

Out-of-universe (e.g. from a TV production standpoint) phaser beams do often travel considerably slower.

As the video below shows, beam speed is wildly inconsistent. At the slowest they seem do seem to be moving about a couple of feet per frame. At the fastest, the beam is instantaneous from one shot to the next

  • That is exactly the answer I was looking for. But if you don't mind I'd like to wait for a possible second opinion before marking it as the right one. To me there is so much consitency standing or falling with this...
    – Einer
    Commented Apr 14, 2014 at 20:33
  • They also travel significantly faster than the speed of light. There are several encounters between Voyager and Kazon ships traveling at warp when phaser fire is exchanged. Or is that a consequence of the warp field?
    – Dacio
    Commented Apr 14, 2014 at 22:49
  • @Dacio - From the same source; img835.imageshack.us/img835/19/3u6h.png - Phasers can be used at warp
    – Valorum
    Commented Apr 14, 2014 at 23:50
  • Doesn't change the fact that, from my sub-light observation frame, those phasers were traveling above light speed.
    – Dacio
    Commented Apr 15, 2014 at 0:05
  • @dacio - Apparently if you've got the right technology you can strap a torch onto a speeding train and have it go faster than lightspeed.
    – Valorum
    Commented Apr 15, 2014 at 0:09

The ST:TNG Technical Manual's description of phaser operation clearly states that the beam will

"travel at c to the target".

Disclaimer: I do not have the book in my possession. Quoting from the Google books version.


In "Wink of an Eye," we see how really slow the beam from a hand-held phaser is (at least, in an atmosphere). When Kirk attempts to "stun" Deela (the "Queen" of the accelerated Scolosians), she is able to slowly step to the side of the beam and allow it to pass by her in order to evade it. Since she can't have been accelerated all that much (at most by a factor of, say, 10,000 times - since at most two subjective days transpire for Kirk in the accelerated state, which would translate to 17 seconds of "ship time" during which Spock, McCoy, and Co. manage to a) realize that the ship has been invaded, and b) whip up a solution), this gives us an upper limit to the beam's speed of propagation.

  • Great answer! Backed up with in-universe, on-screen facts. Commented Mar 8, 2019 at 2:36

Since characters in all of the Star Trek series are shown ducking from and dodging phaser beams, it would seem that their speed is somewhat less than the speed of light and often slower than the speed of a bullet from a projectile weapon. If,as the Voyager Technical Manual states phaser are indeed light speed or even relativistic speed weapons missing with them or dodging their beams would be impossible.

Simply put when someone aims and fires a phaser, there is no way for it not to strike its intended target unless the weapon was deliberately aimed away from them. The weapon has no recoil and it would be as if you shined a flashlight at someone (e.g. you can’t miss them)

  • 2
    That has been my thinking too, but think about it: When you see someone pointing a flashlight at you and you see that he is about to activate it, you can always jump behind a rock. If you detect a phaser lock you can still do evasive maneuvers.
    – Einer
    Commented Apr 15, 2014 at 5:15
  • 1
    @einer - Ship-to-ship evasive maneuvers are intended to present as small a target as possible and to prevent a prolonged exposure to incoming fire.
    – Valorum
    Commented Apr 15, 2014 at 5:35
  • Then why are there cases where someone with hostages can force others to lower their phasers? They can aim their phasers to disable arms or weapons of the hostage keeper?
    – dh16
    Commented Aug 23, 2015 at 5:37

While phasers travel at the speed of light, that does not mean the person firing it has good aim. If you saw a phaser pointed at you, you'd leap too. Granted, that implies the crews of the Enterprises (and Voyager/DS9) came up against some of the worst shooters in the universe who only manage to kill red shirted ensigns, and true, there have been some laughable 'he dodged a phaser' scenes, but the original series was "Wagon Train" in space so I kind of like when ST uses a bit of old western flair in their story telling.

  • Welcome to SFF:SE. Do you have any sources for phasers traveling at the speed of light? I can think of a fair number of counter-examples.
    – Politank-Z
    Commented Oct 31, 2016 at 0:39

The phaser beam has to be traveling much faster 80 k/h, because a passenger plane travels at 926 kph. A phaser beam is going to be exponentially faster because it is almost there instantly. It can reach the surface of a planet from the highest part of a planet's atmosphere almost instantly, too, which means that it has to be traveling at 100s of times the speed of a rocket. In Star Trek: The Next Generation "Encounter at Farpoint," the Enterprise shoots a beam down to the surface that hit the surface almost instantly. However, it also can't be traveling at the speed of light, because phasers don't use photons, and they don't have a warp field to sustain that speed. According to Memory Alpha Star Trek Wiki, phasers and disruptors use nadions, which are artificially generated particles. Here's a link: https://memory-alpha.fandom.com/wiki/Nadion

  • 1
    Could you edit in some evidence to back some of this up I.e. that they’re not made of photons.
    – TheLethalCarrot
    Commented Apr 14, 2020 at 18:21
  • Hi, welcome to SF&F. Please supply some references for your assertions; by preference a video so it's possible for others to check your estimates of the timing. (e.g. an example of a phaser beam travelling from orbit to the surface of a planet.)
    – DavidW
    Commented Apr 14, 2020 at 18:22
  • 1
    Instead of just saying according to the wiki you should add the link and the relevant quote from the page. However it would be even better if you got the primary source i.e, what Memory Alpha is referencing
    – TheLethalCarrot
    Commented Apr 14, 2020 at 21:28

Apart from what is written in "technical manuals", there are inconsistencies across on-screen canon. Within TOS:

  • There is the "Deela" case as mentioned in another answer. Although "hyper-accelerated" such that they can move too fast to be observed by human (or Vulcan) eyes, Scalosians (or their accelerated victims) still have to move through air and don't seem to encounter any relativistic effects regarding incident light, so they're not moving that fast. So, since Deela can side-step the beam of a hand-phaser, it can't be traveling all that fast.
  • There are numerous cases where the Enterprise fires its phasers at some enemy vessel, such as in "Journey to Babel". In that episode, the enemy vessel makes its attack runs at warp speeds much higher than the Enterprise is capable of. Nevertheless, Enterprise attempts to fire on it. Dialog implies that the enemy is outrunning their targeting capability, not the beam itself. After all, why even bother if you already know your enemy can outrun your weapons. So, this would suggest that a phaser beam can travel faster than light... much faster than light.
  • "Journey to Babel" aside, ships battling in space and maneuvering at warp speeds aren't going to be all that close to each other; a phaser beam usually takes less than a second (in most examples) to arrive at its target, which would presumably be kilometers away.

A phaser blast travels at warp fifteen, the maximum speed possible in the Star Trek universe without going into time warp. In the original series "The Ultimate Computer", the M5 computer easily destroys two Federation Star Ships while the Enterprise is traveling at warp four. In the original series "Journey to Babel", Captain Kirk destroys a scout ship with a phaser blast that is traveling at warp ten.

Unfortunately, there have been many writers of Star Trek since the original series that had very little understanding of the firepower of the original Enterprise and they weakened the Enterprise significantly in the movies and the Next Generation. In the original series "The Changeling" the Nomad robot repeatedly attacks the Enterprise with energy blast that are each equal to ninety photon torpedoes. The original Enterprise was far more powerful than the future ships that the writers weakened. The original Enterprise's photon torpedoes were dirty bombs that could destroy a city.

  • The first paragraph seems to have some bearing on the question. The second paragraph has little or no bearing and is basically a rant.
    – Valorum
    Commented May 13, 2015 at 18:16
  • By no means was it meant to be a rant. I was simply stating factual events that took place with Gene Roddenberry's original version of Star Trek. The writers after him changed a lot concerning the Enterprise's firepower and endurance making it difficult for an accurate answer to the question. I simply went back to the old episodes for the best answer I could give.
    – Ray
    Commented May 13, 2015 at 18:34
  • 1
    So you're just going to ignore that Roddenberry was intimately involved in the writing, production and direction of TNG?
    – Valorum
    Commented May 13, 2015 at 18:37
  • As well as utterly ignoring that writers were presented with a very comprehensive show "bible" that explained the capabilities of the various bits of tech lying around?
    – Valorum
    Commented May 13, 2015 at 18:38
  • Of course Roddenberry was involved. They had to lower the firepower so they could have an awesome Star ship battle in Star Trek 2 The Wrath of Kahn. The bottom line is the original 1968 Enterprise from the original series would totally blow away Picard's flying window pane Enterprise. They had to lower the firepower to make great Star ship battles with today's special effects.
    – Ray
    Commented May 13, 2015 at 18:46

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